Ordesa y Monte Perdido National Park.
Ordesa Valley is praiseworthy for constituting the germ of the current National Park. It is also its main entrance and its most visited area.
With a difference in height of more than 2000m. from the uppermost summit down to the lowest point of the valley, Ordesa Valley is a magnificent canyon extended along 13 km, bulldozed by ancient glaciers and the strength and persistence of the Arazas River, which makes its way down to its confluence with the Ara River.
During the Pleistocene glaciations, thick ice sheets moved through Ordesa down to the Broto valley, forming characteristic "U"-shaped valleys, scarped walls, cliffs, faults, horizontal clefts, carved by the different resistance to the erosion of the limestone bedrock constituting the valley.
In its uppermost area, we can find large extensions of polished rocks, cracked and fluted by characteristic trenches in a stone landscape. Flowing down to the valley, later river erosion deepened the river basin, as showed in ravines and cascades along its course: Cascada de la Cola de Caballo, Gradas de Soaso, Cascada del Estrecho...
And everything surrounded by forests, preserved in its natural state, especially red pine forests on sunny slopes, beech forests in shady areas and fir and black pine forests in the highest and roughest terrain.